1. Field of the Invention
The present invention relates to a capotasto of the kind with a clamping bar which is intended to extend transversely over the fingerboard on the neck of the stringed instrument.
2. Prior Art
U.S. Pat. No. 5,016,514 teaches a capo which, according to one embodiment, includes a bar that has a recess at one end thereof. A straight highly elastic, plastic tubular member has an end part fitted on the bar and fixed thereto. The remainder of the tubular member extends around the neck of the instrument and has a screw at one end. The neck of the screw is received in a recess in the bar. The tensioned state of the capo can be adjusted, by screwing the screw deeper into the end of the tube. According to another embodiment of the capo taught by U.S. Pat. No. 5,016,514, the spring member includes a coiled tension spring and the bar includes a bore hole at each end. A screw extends through respective bore holes into the end of the coil spring. The coil spring is covered with an elastic sheet.
Examples of known capos of this kind are described in U.S. Pat. No. 3,185,012, U.S. Pat. No. 3,598,012, U.S. Pat. No. 3,823,247, U.S. Pat. No. 3,903,776, U.S. Pat. No. 4,183,279, U.S. Pat. No. 4,475,433 and U.S. Pat. No. 4,823,670.
A capo will preferably be capable of fulfilling several different requirements, as far as possible. It should be easy to remove and fit the capo to and from the neck of the instrument, and also capable of being easily moved to desired positions along the instrument""s neck and there quickly fastened in a simple manner. The capo should present the smallest possible obstacle to hand movement along the neck of the instrument and it should also minimise unintentional changes in pitch.
The aforesaid known capos are unsatisfactory with respect to one or more of the above requirements.
Accordingly, one object of the present invention is to provide a capo which essentially satisfies the requirements.
Other objects of the invention and advantages afforded thereby will be apparent from the following description, or can be perceived therefrom.
These objects are achieved with an inventive capotasto that has the features that include a clamping bar which is intended to extend transversely over the fingerboard on the neck of a stringed instrument. A tensioning device is provided and it includes a resiliently bendable tensioning strap.
The strap has two end parts, and one of the end-parts is essentially flexurally rigid and connects generally perpendicularly with one of the ends of the clamping bar. The other end can be detachably connected to the other end of the bar with the aid of fastening means, so as to clamp the bar securely against the fingerboard with a clamping force. The tensioning strap is free-standing from the clamping bar in its non-tensioned memory state, and the one end-part of the tensioning strap is directed at its connection with the bar in a manner such as to diverge from an undersurface of the neck when no tension is applied to the tensioning strap. The tensioning strap has a non-tensioned state and the non-tensioned state is a memory form in which the strap holds the components of the fastening means close to their mutual position of engagement.
The tensioning strap is pre-formed such that when initially tensioned, it will contact the neck in a peripheral region that lies beyond a symmetrical plane of the neck from a corner angle between the one bar end and the one end-part of the tensioning strap. Accordingly, a force resultant to the area of contact of the strap with the neck holds the neck corner in engagement with the corner angle when the capotasto is tightened.
Further embodiments of the inventive capotasto are that the other end of the tensioning strap is designed to generate an initial displacement effect that causes a neck corner to be driven into a corner angle as parts of the fastening means are brought into fastening engagement.
Also, in another embodiment, the tensioning strap is integral with the bar, and the fastening element is comprised of a screw carried by the tensioning strap, and a nut carried by the screw. The other end of the bar includes a recess which is open, and the recess opens towards the other end of the bar and receives the screw.
The capotasto also defines the nut as generally conical having a narrower end, wherein the narrower end of the nut is for resting against an edge of the recess.
Other features of the capotasto are that the other end of the bar is rounded at the recess, and a thicker end of the nut includes a semi circumferential edge flange.
The capotasto has a side of the bar that faces towards the fingerboard and carries a clamping pad which includes on the side facing towards the bar an undercut projection which is snapped. The undercut projection is for snapping into a corresponding undercut groove in the bar, and the tensioning strap is essentially non-stretchable in its longitudinal direction.
The fastening element includes a rod which is fixed to the free-end of the strap and carries a row of teeth. Another tooth, located on the free-end of the bar, is intended for engagement with the row of teeth. The mutually co-acting teeth are directed to facilitate closure of the components of the fastening element and to counteract separation of the components along the row of teeth.
The inventive capo includes a clamping bar which is intended to extend across the finger board on the neck of a string instrument, and a tensioning means which includes a resiliently bendable tensioning strap whose one end is essentially flexurally rigid and connects with one end of the bar essentially at right angles thereto, and whose other end can be detachably connected to the other end of the bar by means of a fastening device, such as to tension the bar against the fingerboard with a desired clamping force, wherein the tensioning strap is free-standing from the bar in its non-tensioned memory state, and wherein at its junction with the bar said one end-part of the tensioning strap is directed so as to diverge from the adjacent surface of the neck of the instrument when the strap is not under tension. The memory shape of the tensioning strap is such that the parts of the fastening device will be held close to their mutual positions of engagement in the non-tensioned state of the capo. The strap is constructed so that as it is tightened it will initially contact the neck of the instrument in a circumferential region that lies beyond the symmetry plane of said neck, as seen from said one end-part, whereby a force resultant to the initial pressure-contact area of the strap against said neck will tend to pull an angled corner defined by one end of the bar and one end-part of the tensioning strap into engagement with the adjacent corner on the neck of the instrument as the fastening means is tightened.
The other end-part of the tensioned strap is configured and directed so that when in contact with the adjacent peripheral part of the neck of the instrument it generates a wedging effect which causes the capo to be displaced so that said corner receives the adjacent corner of the neck as the parts of the fastening means are fastened together.
Because the capotasto strap has a memory form and a degree of springiness such that the capotasto will lie shape-bound around the neck of the instrument even though subjected to gravitational forces, the capo will not fall from the neck of the instrument even when the fastening device is open. When open, the capotasto will normally be free to move along the neck of the instrument while, as before mentioned, the components of the fastening means are constantly in the immediate vicinity of each other and therewith readily fastened by the user.
In preferred embodiments of the invention, the components of said fastening means can be snapped into effective engagement with one another with finger force. The fastening means may alternatively include a screw/nut tightener which will enable the fastening or tensioning force to be adjusted.
Because the force resultant of the surface pressure of the strap against the neck of the instrument is directed towards the inner corner defined by said one end of the bar and said one end-part of the strap, the capo will remain in its initial position.
The tensioning strap is elastically flexible in at least that end-part which connects with the one end of the bar. The one end of the tensioning strap is connected to the bar so as to be flexurally rigid at the connection point and is directed so as to diverge from the undersurface of the neck when the strap is not under tension. As a result, the capotasto will project minimally beyond the cross-sectional profile of the neck of the instrument on the discant side, while the adjacent outer edge of the fingerboard is received stably in the corner defined by the bar and the tensioning strap. Furthermore, the force resultant of the contact forces of the tensioning strap against the underside of the neck will be directed generally towards the corner angle, therewith holding the capo stably in its set position on the neck of the instrument. The aforesaid corner also forms an anvil means against which the edge of the fingerboard is placed when fastening the capotasto. This eliminates the risk of the strings being pulled obliquely by the capo as it is being secured to the instrument (this being one cause of undesirable pitch changes).
Although the inventive concept can be applied with several earlier types of capo, it is preferred that the fastening means of the capo is located at that end of the bar which lies opposite to the end that carries the tensioning strap, so that the fastening means will be able to fit in the gap between the finger tips and thumb of one hand with said hand placed typically around the neck of the instrument and moved therealong. As a result of the position of the fastening means, the minimised projection of the bar on the discant side of the fingerboard, and because the capo as a whole can be given a very slender construction owing to the fact that the major part thereof is subjected to tension forces, a capo that is constructed in accordance with the inventive principle will encroach on the space of the user""s hand only to a very small extent. This enables the capo bar to be placed close to the top of the gripping strap without impeding the hand to any appreciable extent. The gripping strap will then function as an anvil means and prevent the strings from being depressed more than is necessary. Another, and more common, reason why tuning of an instrument is impaired when using a capo (both in relation to accompanying instruments and to the individual strings of the instrument being accompanied) is precisely because the capo presses the strings down against the fingerboard to an unnecessary extent.
According to one particularly preferred embodiment of the invention, the essentially rigid capo bar is integral with the tensioning strap, wherein at least the end-part of the tensioning strap that adjoins the capo bar is semi-rigid (i.e. elastically flexible under the influence of the fastening means), wherein the end-part of the tensioning strap connecting with said fastener means is preferably given a slightly reduced flexural rigidity in the plane of the capo, wherein the end-part of the fastening strap carries an upwardly extending screw and is held in the immediate vicinity of or in engagement with a recess at the free-end of the capo bar, by virtue of the stiffness of the strap and its attachment to the capo bar, wherein a nut may be screwed onto the screw to enable the tensioning force generated by the capo to be adjusted. The nut may have a general conical shape, so as to enable it to be easily snapped into and out of engagement with the edge of the recess.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.